How to Resolve These Seven Error Codes on Your Nest Thermostat

August 15, 2022

Operating a Nest thermostat is one of the easiest ways to perfect the day-to-day schedule of your comfort system. This smart thermostat can be taught your preferences and automatically make adjustments. But as you might expect, it won’t work well or at all if you see an error code on the display. The precise error code offers useful information about the root of the problem, something a trained technician can use to provide solutions that much faster.

Here are seven of the most frequent error codes you may discover on your Nest thermostat. We’ll explain the basics of each error code as well as how you can fix it and the projected cost to do so. Remember that while the costs will ultimately depend on the exact Nest model, you can anticipate paying around $75-$200 for repairs. This should also cover travel and labor costs on top of any specific parts required to finish repairs.

e298 - Critical

This critical error code is limited to new models of the Nest thermostat and is displayed when the power is shut off. Because this is a critical power error, the thermostat will change to the backup battery system. The error message will remain on the screen until the problem is fixed.

Losing power to your Nest thermostat can be for a number of reasons. The wiring may have disconnected or become damaged, or a disconnection could have appeared further along in your electrical system. This may be the circuit breaker, fuse box or system switch. A knowledgeable technician can check electrical connections and wiring until they uncover the source of the problem.

e294 - Critical

Critical error code e294 is displayed when your Nest thermostat’s wiring has to be reconfigured. More specifically, the technician should reconfigure the R wire. They’ll first conduct a factory reset of your thermostat to make sure it’s not just a software error. If that doesn’t work, they’ll check the wiring diagram of the thermostat and begin inspecting connectors.

They’ll detach the power and gradually inspect each wire, making sure they are fully attached into the connector with the correct amount of uncovered copper. When they pinpoint the damaged connector, it can be swapped for a new one.

e195 - Critical

This critical error code can surface when the weather outside is especially hot. The HVAC system can fail and stop giving power to your Nest thermostat. When this problem lasts, the backup battery in your thermostat depletes and the thermostat will eventually shut down. In the event the breakers are on, you can inspect a couple of other places before calling a professional technician.

Since this error can consume your thermostat’s battery, the first step could be providing enough power to find out if this specific error code is what you’re working with. You can disconnect the thermostat from its base and deliver power by using a USB cable. If it presents error code 195, you should continue to visually examine components including the wiring as well as your air conditioner’s air filter or drainage system. If you don’t detect anything wrong with these components, it will likely be best to get in touch with a pro.

e103 - Critical

Another critical error code, e103 signifies an electrical malfunction with your Nest thermostat. More specifically, e103 will refer to an overcurrent problem, which means the wiring is experiencing more power than necessary. This may stem from the breaker box, an error from the control board or thanks to a faulty connection in the thermostat. The technician should carefully inspect and test the Nest’s electrical system to determine where the power is surging or why the thermostat believes there’s an overcurrent problem.

n260

While this error code isn’t critical, it might still prevent you from using the Nest thermostat how you want to. Error code n260 refers to the lack of a C wire or Nest Power Connector, as the absence of one can block your Nest from obtaining sufficient power. You can examine the Nest’s C connector for the presence of a C wire and modify the wiring itself if there is. If not, you can get a Nest Power Connector.

During installation of a Nest Power Connector, you might notice error code E297 be displayed. This can be remedied by updating your thermostat in Settings -> Software -> Update. If the Power Connector is already installed, you’ll instead be required to update the wiring info in the app from Settings -> Thermostat -> Wiring -> Update wiring.

e104 - Critical

Similar to error code e103, e104 is a critical error that's the result of an overcurrent. If excess power is sent using the Nest’s wiring, it can damage internal components and may even be a fire hazard. If you notice this error code pop up on your Nest thermostat and want to guard against electrical damage, it’s recommended to turn the power off as soon as possible. You can then contact a professional technician with the proper experience detecting and resolving electrical damage.

e73 - Critical

When your thermostat displays error code e73, it means that the Rc wire is not receiving power. This might be as easy as the breaker being switched off, but it could also be a problem with the wiring. After switching off the power to your HVAC system and thermostat, you can visually inspect the wires to make sure nothing is loose or damaged. If nothing appears to be out of place, it’s time to speak with a local professional.